Methods and apparatus for removing defective casing or pipe from well bores



3,087,546 ECTIVE April 30, 1963 B. J. WOOLLEY METHODS AND APPARATUS FOR REMOVING DEF CASING OR PIPE FROM WELL BORES 5 Sheets-Sheet 1 Filed Aug. 11, 1958 Brown 0/. WovV/ey INVENTOR. WM BY 013 2 Z -uJO/M hupw Q 7 ATTORNZYJ April 30, 1963 B. J. WOOLLEY 3,087,546

METHODS AND APPARATUS FOR REMOVING DEFECTIVE CASING oR PIPE FROM WELL BORES 5 Sheets-Sheet 2 Filed Aug. 11, 1958 5/0 W/7 (Z We o//e y INVENTOR. Mayra/ BY April 30, 1963 B. J. WOOLLEY METHODS AND APPARATUS FOR REMOVING DEFECTIVE CASING OR PIPE FROM WELL BORES 5 Sheets-Sheet 3 Filed Aug. 11, 1958 Brawn d, Woo //e u INVENTOR.

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Q/yl/h ATTOR/V/FYS April 30, 1963 B. J. WOOLL EY 3,087,546

METHODS AND APPARATUS FOR REMOVING DEFECTIVE CASING OR PIPE FROM WELL BORES Filed Aug. 11, 1958 5 Sheets-Sheet 4 '1'Auit'lmiim f' Brow/7 W00 li m ma aw //ey INVENTOR. M

ATTORNf/J April 30, 1963 METHODS AND APPARATUS FOR REMOVING DEFECTIVE Filed Aug. 11, 1958 I II B. J. WOOLLEY 3,087,546

CASING OR PIPE FROM WELL BORES 5 Sheets-Sheet 5 all Brown J. Wao/Aey v INVENTORLM BY 5 m M ATTORNEYS United States Patent 3,087,546 METHODS AND APPARATUS FOR REMOVING DE- FECTIVE CASING OR PIPE FROM WELL BORES Brown J. Woolley, P.O. Box 1249, Kilgore, Tex. Filed Aug. 11, 1958, Ser. No. 754,463 15 Claims. (Cl. 166-46) This invention relates to new and useful improvements in methods and apparatus for removing defective casing or pipe from well bores.

The method and apparatus herein disclosed is an im provement upon the method and apparatus shown in my co-pending application, Serial No. 496,790, filed March 25, 1955, now Patent No. 2,848,050.

It is one object of this invention to provide an improved method and apparatus having all of the advantages of the method and apparatus disclosed in my previous application but, in addition, having other features which add to the versatility of the apparatus, whereby eflicient performance under various conditions is assured.

An important object is to provide an improved method for separating and removing a defective portion of a well pipe from a well bore and thereafter lowering a re placement section of pipe, wherein a combination casing separating and line-up apparatus is lowered, properly positioned, operated and then supported within the unre moved section of the well pipe, whereby the entire operation may be carried out with a single run of the combination apparatus; the method permitting the apparatus to be located in one position throughout the complete operation or in the alternative, permitting the tool to be raised after the casing-separating step to locate the line-up assembly in desired position for subsequently guiding the replacement section into position.

A further object is to provide an improved apparatus wherein standard type cutting tools, either mechanically or hydraulically actuated, may be employed in the assembly and also wherein a collar finder device may be employed for properly positioning the cutting tool and for subsequently supporting the apparatus within the pipe being repaired.

A further object of the invention is to provide an apparatus which includes, a pipe cutter, a line-up or guide element and a slip type supporting means, with the latter being actuated by manipulation of the string upon which the apparatus is mounted, whereby said supporting means may be utilized to support the apparatus at the desired point within the pipe being repaired.

Still another object is to provide an apparatus of the character described, wherein the line-up or guide element may be formed to the outer body of the cutting tool or wherein a separate line-up device may be positioned, either above or below the cutter; said separate line-up device having readily removable guide elements which may be easily changed to adapt said device to various diameter pipes.

Still another object is to provide an apparatus of the character described, which may include an inside pipe cutter, a line-up member, a collar finder device and a slip-type supporting means; said elements being arranged in any desired order with relationship to each other in accordance with the particular manner in which it is desired to support the apparatus within the lower undamaged section of the pipe being repaired.

The construction designed to carry out the invention will be hereinafter described, together with other features thereof.

The invention will be more readily understood from a reading of the following specification and by reference to the accompanying drawings forming a part thereof, wherein an example of the invention is shown, and wherein:

FIGURE 1 is a view partly in section and partly in elevation showing an apparatus, constructed in accordance with the invention, lowered within the well casing with the collar finder device locating a casing collar;

FIGURE 2 is a similar view showing the position of the elements during the cutting step of the method;

FIGURE 3 is a similar view illustrating the apparatus in supported position during the lowering of the replacement casing;

FIGURE 4 is a view similar to FIGURE 1 showing a modified form of apparatus which includes a line-up assembly or joint;

FIGURE 5 is a view similar to FIGURE 4 but illustrating the apparatus in a higher position Within the well casing with the line-up assembly located to guide the replacement section into final position;

FIGURE 6 is a view similar to FIGURE 4 and showing still another modification of the apparatus wherein a supporting tool is employed to support the apparatus within the well casing;

FIGURE 7 is a view similar to FIGURE 6 but illustrating the line-up assembly between the collar finder device and the supporting tool;

FIGURE 8 is a longitudinal sectional view of one type of hydraulic cutter tool which may be employed;

FIGURE 9 is a longitudinal sectional view of a mechanically operated cutter tool which may be employed in the apparatus;

FIGURE 10 is an enlarged sectional detail showing one of the guide elements of the lineup assembly;

FIGURE 11 is a longitudinal sectional view of one type of collar finder device which is applicable for use with the apparatus, said collar finder device having an automatic bottom type of connection;

FIGURE 11a is an enlarged elevation of a J-slot connection which may be substituted for the automatic bottom type connection shown in FIGURE 11;

FIGURE. 12 is a longitudinal sectional view of one type of supporting tool which may be employed in the apparatus, said tool having a J-slot connection at its lower end, and

FIGURE 12a is an elevation of an automatic bottom type of connection which may be substituted for the J-slot connection shown in FIGURE 12.

In the drawings the numeral 10' designates a well casing which extends downwardly from the surface within a well bore W. The casing includes the usual pipe sections or joints which are shown as connected together by casing collars 11 although said casing sections could be secured together by welding. The casing is supported at the surface of the well by a suitable casing head assembly generally indicated at -12 in FIGURE 2. Any suitable type of well-known casing head assembly may be employed and a simplified illustration of one type is shown. It often occurs that a defect will occur in one of the casing sections and it becomes necessary to remove a portion of the casing and replace the defective portion with a replacement section. In FIGURE 1 an opening .13, which may have been caused by corrosion or by other causes, is illustrated in one of the joints of the casing 10. When such a defect occurs, it is desirable to sever the casing 10' at some point below the defect, remove all casing above the point of severance and then insert a replacement section into the well bore, which replacement section is reconnected to that part of the casing still remaining in the bore by the usual well-known patch methods.

The present invention is concerned with an apparatus and method which will facilitate the cutting and removal of the defective portion of the casing followed :by the subsequent lowering of a replacement easing into the well bore. As illustrated in FIGURE 1, the apparatus includes an inner or lowering pipe 14 upon which the apparatus of this invention is adapted to be lowered within the well casing 10. An inside pipe cutter tool A is connected to the lower end of the pipe 14 and is provided with expansible cutters 15, which when operated will sever or cut the Well casing 10. As will be explained, the cutter tool A may be any of the well-known types of cutter tools now in general use and may be either hydraulically actuated by directing fluid pressure downwardly through the inner pipe 14 or may be mechanically operated by manipulating said pipe.

Spaced below the cutter tool A is a collar finder device B which is connected with the lower end of the tool A through a spacer joint 16a and collar 16. The device B is provided with radially expansible dogs 17 which are adapted to engage the annular recess 11a which is formed in the usual coupling collar of the well casing; if the casing joints are welded, the dogs 17 will co-act with the annular recess formed in the weld. tlFor purposes of this description, it will be assumed that coupling collars 11 are employed. As will be explained, the device B is adapted to be actuated by manipulation of the pipe 14 and when its radially movable dogs 17 are in position to engage the recess 11a of a collar, said device functions to locate or find such collar. The primary purpose of a collar finder device is to locate the cutter tool A in a position where its cutters 15 will be disposed to cut through the wall of the casing 10, rather than being located at a joint or collar in the casing.

Extending downwardly from the collar finder device B is a downwardly extending pipe section 18 upon the lower end of which is secured a tapered or conical guide member 19. This guide member is preferably formed with annular teeth 20 whereby entry of the assembly into a flattened part of the W611 casing is facilitated. If desired, a suitable length of tail pipe 21 may extend downwardly from the guide member 19.

In the form of apparatus illustrated in FIGURES 1 to 3, the outside or external diameter of the outer body 22 of the cutter tool A is such that said body fits within the bore a of the casing 10 with a slight clearance. Since the cutter body 22 is of substantial length, said body actually forms a line-up or guide element for guiding a replacement casing into position, as will be hereinafter explained.

In using the apparatus and practicing the method as illustrated in FIGURES 1 to 3, the defect 13 in the casing 10 is first located by any suitable means so that its elevation or position is known to the operator. Thereafter, a suitable plug-type packer P is set within the casing 10 at some distance below the defect 113; this packer includes a packing element 23 and gripping slips 24 and may be of the usual well-known construction, whereby when said packer is in set position, the bore of the well casing is closed.

After the packer *P has been set, the apparatus which includes the cutter tool A and collar finding device B is lowered downwardly within the well casing to locate the collar finder device at some point below the defect 13. The device B is then moved into a position to permit expansion of its radially movable dogs or elements 17 and upon continued downward motion said dogs will engage the recess 11a of one of the casing collars 11. Thus the device B finds the collar and this assures the operator that the cutters of the tool A are properly located at a point between casing collars.

Thereafter, by manipulation of the pipe 14, retraction of the dogs 17 of the device B is efiected and the entire assembly is raised slightly to release the dogs 17 so that the pipe 14 may undergo free rotation relative to the collar finder. The inside cutter tool A is then actuated, either hydraulically or mechanically, to move the cutters 15 of the tool A outwardly in the manner shown in FIGURE 2 whereby the casing 10 is severed or cut at the point 25 to separate the portion of the casing above the cutters from the casing therebelow. Following severance of the pipe, the assembly may be slightly lowered and the dogs 17 again expanded to engage within the recess 11a of the casing collar and thus the apparatus as well as the inner or lowering pipe .14 will be supported by the engagement of said dogs within said recess.

It is then possible to remove the upper portion or the defective casing 10 by stripping it upwardly over the inner pipe 14. This is possible by first removing any sections of the inner pipe 14 which are above the collar 14a at the surface (FIGURE 2) and then removing that portion of the casing above the cut 25, joint by joint in the usual way by means of the derrick equipment. In this manner the defective portion of the'well casing 10 is removed from the well bore but it is pointed out that the apparatus including the cutter device A, the collar finder device B and the inner pipe 14 remain within the well bore.

A replacement section of easing indicated at in FIGURE 3 is then lowered downwardly within the well bore. This replacement section is provided with the usual patch connection generally indicated at 112 at its lower end, this patch section 112 being adapted to telescope over the upper end 10b of that part of the casing 10 which remains within the well bore; as is well known, the usual patch section includes gripping elements which engage the exterior of the casing remaining in the bore and also includes a suitable sealing arrangement. As the replacement section is lowered downwardly through the well bore, it is guided by the inner pipe 14 which is supported at its lower end by the collar finder device B. Since the external diameter of the body 22 of the cutter tool A has very little clearance between the bore 10a of the casing, the body 22 of the cutter tool A will function as a line-up element and will assist in guiding the replacement section of casing 110 into position. After the replacement portion 110 of the casing is in position, the patch section 112 is actuated to connect the replacement portion to the casing therebelow and thereafter the inner pipe 14, cutter tool A and collar finder device B may be removed from the well. It is noted that the cutting of the defective casing, removal of the same and re-running of the replacement section are accomplished without having to remove the apparatus from the well bore.

As illustrated in FIGURES 1 to 3, the apparatus is sup ported in substantially the same position said apparatus had at the time that the cut 25 was made. However, it is obvious that the tool could be lowered to any collar 11 of the casing which is below the point of severance. Of course, it is desirable when the replacement section 110 is being guided in position that the body 22 of the cutter tool be located so as to project upwardly above the upper end 1% of that part of the casing still remaining in the hole, whereby said tool body may function as a guide element. If the apparatus has been supported in some collar below the collar shown in the drawings, it would, of course, be necessary to raise the apparatus to properly locate the cutter tool body just prior to the time that the replacement section 110 of the casing is brought into final connected position.

In the arrangement shown in FIGURES 1 to 3, the collar finder device B is employed as a combination unit which is first utilized to locate or find a collar so as to properly dispose the cutters 15 of the cutting tool in proper position to perform the cut and is, thereafter, employed as a means for supporting the apparatus and inner pipe within that portion of the casing still remaining within the bore. Also, in this form of the invention the outer body 22 of the cutter tool is made of such diameter as to form a guide element so that a separate line-up or guide element need not be provided since the tool A functions not only as a cutting tool but also as a guide element. By providing the tools with two separate functions, the apparatus may be greatly simplified which is of an economical advantage.

The cutter tool assembly A may, as above noted, be either hydraulically or mechanically actuated and any well-known tool now on the present market may be employed. In FIGURE 8 one type of hydraulically actuated cutter tool is illustrated. As shown in this figure, the outer body 22 of said tool has its upper end connected at 26 to the lowering or inner pipe 14. The lower end of the body is connected through a coupling 27 with the connecting section 16, which extends downwardly to the collar finder device B. A tubular mandrel 28 is formed within the bore of the body 22 and an annular piston 29 is slidable within a cylinder 30 formed within said body. The piston 29 has a tubular extension 31 which is slidable on the mandrel 28 and said extension is formed with a cutter expander 32 at its upper end. A coil spring 33a normally maintains the piston and the expander in lowered position. The cutters 15 are pivoted on pins 33 and are disposed within radially extending slots 34 provided in the wall of the body 22.

Normally, the various elements of the tool illustrated in FIGURE '8 are in the position with the coilspring 33a maintaining the piston 29 in its lower position whereby the expander 32 is in its lowered position and the cutters 15 are retracted. This is the position of the parts when the tool is lowered into the well bore. When it is desired to actuate the tool, a closure, preferably in the form of a ball 35 is dropped downwardly through the pipe 14 and engages the seat 36 formed in the coupling 27 to close downward flow of fluid through the tool. Upon the building up of pressure within the tool, such pressure acts on the lower side of the piston 29 and moves said piston upwardly which motion is transmitted to the expander 32 to effect an expansion of the cutters 15. By maintaining the pressure on the tool, the cutters are maintained in their outward position and through notation of the tool by means of the pipe 14, the cut ting operation is performed.

Another type of cutter tool which is applicable for the present purpose is shown in FIGURE 9. This tool is a mechanically operated tool, as distinguished from hydraulic, and includes an outer body portion 22a which is reduced to form a downwardly extending mandrel 22b. The cutters 15 are mounted on suitable pivot pins 37 and their lower ends are adapted to co-act with an expander 38 which surrounds the mandrel portion 22b. The expander 38 normal-1y floats on the mandrel section 2% and is formed with a tapered surface or cone 39 at its lower end. This surface is adapted to co-act with gripping slips 40 which are carried by a sleeve 41. The sleeve 41 is formed with the usual J-slot 42 and is adapted to connect with the mandrel section 225 by means of a pin 43 which engages in said J-slot. Suitable friction or drag springs are mounted on sleeve 41 and will serve to maintain the slip assembly 40 stationary when the pin 43 is moved into the longitudinal portion of the J-slot 42.

The operation of the mechanical type cutter tool is believed obvious. The tool is lowered into position with the parts as shown in' FIGURE 9, the pin 43 being engaged within the J-slot 42 to retain the slips 40 in a retracted or lowered position; at this time, the cutters 15 are also retracted. When it is desired to actuate the tool, the pipe 14 is manipulated to align the connecting pin 43 of the mandrel section 2211 with the longitudinal portion of the J-slot 42, after which the pipe 14 and body of the tool are lowered. At this time the friction springs 44 hold the gripping slips 40 stationary and as the body portion 22a and mandrel section 22b of the tool move downwardly, the cutters 15 are moved downwardly with respect to the upper tapered surface of the expander 38. Initially, because the angle of contact between the cutters and upper end of the expander is greater than the angle of contact between the lower end of the expander and the slips, the exander 38 moves downwardly with respect to the slips 40* and through the co-action of the expander surface, the slips are expanded after which the expander is locked against further downward motion. Continued lowering of the tool body causes the cutters 15 to be ex panded by the upper inclined surface of the expander 38 and by maintaining weight on the body through the lowering pipe 14 and at the same time rotating said pipe, the cutting operation is performed. Removal of the tool is effected by lifting upwardly on the body section and reengaging the pin 43 with the J-slot 42 to again latch the slips 40 in their nongripping position.

Various types of collar finder devices may be employed and one type which has been found satisfactory is illustrated in FIGURE 11. As shown in this figure, the device comprises a central tubular mandrel 50 which has its upper end connected to the connecting section 16 which attaches the device to the cutter tool A. The mandrel 50 extends completely through the tool and has a coupling collar 51 threaded onto its lower end. The collar 51 is a special type of coupling and has an upper extension 52 which is provided with annular teeth 53 on its external surface. The teeth 53 are engageable by dogs or slip members 54 which are carried within a tapered supporting element 55. The element 55 is threaded within the lower end of an outer housing 56 which encircles the mandrel 50. interposed between the housing 56 and the mandrel 50 is an elongate sleeve 57 which has an expander 58 at its extreme upper end. The sleeve 57 and expander are slidable longitudinally within limits on the exterior of the mandrel 50.

The outer housing 56 is formed with radial slots 59 and the radially expansible dogs or supporting elements 17 are movable within these slots. Each dog is formed with an inclined surface 17a at its upper end which coacts with the expander surface 58 at the upper end of the tubular sleeve 57. Thus, when the sleeve 57 moves downwardly with respect to the dogs 17 said dogs are moved radially outwardly into expanded position. The outer housing 56, which carries the dogs 17, also has friction or drag elements 60 mounted thereon, these elements being in the form of shoes which are constantly urged in an outward direction to drag on the bore of the pipe by springs 61.

The collar 51, which is secured to the lower end of the mandrel 50, has its lower portion formed with an enlarged head 51a whereby an external shoulder 62 is formed. Extending upwardly from this shoulder is a lug 63 which is engageable by a depending lug 64 pro- 'vided on the lower end of the supporting element 55. It is pointed out that the connection, which is made by the teeth 53 on the exterior of the collar extension 52 and the dogs or slip elements 54, is generally known as an automatic bottom. This connection may be separated by rotating the mandrel with respect to the dogs 54 so that the teeth 53 are unscrewed from said dogs; reconnection of these members may be made upon a straight longitudinal movement of the mandrel upwardly with respect to said dogs.

In the operation of the collar finder device, the parts are lowered within the well casing with the connection made up as shown in FIGURE 11. When the device is to be actuated to permit expansion of the dogs 17, the pipe 14' is rotated in a direction to the right to rotate the mandrel 50 and the collar 51 at its lower end in a direction to the right. .The threads 53 on the extension 52 of the collar 51 are left-hand threads and as the ma drel 50 is rotated to the right the threads 53 are unscrewed @rom the slip or connecting elements 54. The position of the lugs 63' and 64 is such that rotation in this direc tion is possible since it moves the lug 63 away from the lug 64. By the time that the collar 51. has rotated one fiull turn, lug 63 is moved downwardly by reason of the unthreading action so that the lugs are clear and continued disconnection of the threads 53 may be accomplished. During this time, the locking or slip elements 54 are maintained stationary because they are mounted,

preferably by a dovetail connection (not shown), within the outer housing 56 which is held stationary by the friction shoes 60. As soon as the connection between the threads 53 and the slip elements 54 is broken, the mandrel 50 and the slip expander sleeve 58 carried by said mandrel may be moved downwardly relative to the outer housing. This results in a downward movement of the slip expander 58 with respect to the locking dogs and expands said dogs into their radially expanded position so that as soon as said dogs reach one of the recesses 11a in the casing collar 11, said dogs fall into said recess in the manner shown in FIGURE 1. When it is desired to retract the dogs 17, it is only necessary to pull upwardly on the inner mandrel 50; due to the type of threads 53 which are of a ratchet type, the upward longitudinal movement of the mandrel will re-engage the coupling 51 with the slip elements 54 to reconnect the mandrel with the outer housing. The lugs 63 and 64 limit a left-hand rotation of the outer housing or casing with respect to the mandrel when the parts are in connected position and function to prevent excessive tightening of the left-hand threads whereby assurance is had that the friction blocks will hold the outer housing stationary when said lefthand threads are to be disconnected. It is apparent that with the connection shown, the mandrel 50= may be manipulated to either effect expansion or contraction of the dogs at any time. Thus, the dogs may be selectively expanded and retracted as conditions require.

Although the automatic type bottom connection between the mandrel 50 and its outer housing or casing 56 makes it possible to quickly reconnect the mandrel with said housing, other types of connections could be used. For example, an ordinary J-type of connection could be provided on the lower end of the collar finder device of FIGURE 11 and in FIGURE 11a such a construction is shown. In this case, the lower end of the mandrel 50 carries a coupling element 151 which has its upper portion reduced as shown at 152 with said portion being provided with a radially extending pin 153. Instead of the slip type elements 54, the lower portion of the outer housing 56 is formed with a coupling collar 154 having a J-type slot 155 therein. This slot is adapted to receive the connecting pin 153. v

The operation of this modification is obvious.- When the pin 153 is engaged with the slot 155, the mandrel 50 and the outer housing 56 are connected together to prevent expansion of the locking dogs 17. Upon a rotation and downward movement of the mandrel with respect to the outer casing 56 which is held stationary by the friction shoes 60, the inner mandrel 50 may be lowered with respect to the outer housing and this moves the expander 58 with respect to the dogs 17 to effect an expansion thereof. Thus, the dogs 17 may be selectively expanded or retracted.

In the formapparatus illustrated in FIGURES 1 to 3, the cutter tool A has been described as having its outer diameter of sufiicient size to function as the line-up element or guide for guiding the replacement section 110 of the casing into final position. However, in some instances it may not be desirable to employ the outer housing of the cutter tool as the guide element and in such event an arrangement such as shown in FIGURE 4 may be employed. Referring to this figure, the apparatus includes the lowering pipe 14, having the cutter tool A secured thereto. Disposed between the cutter tool A and the collar finder device B is a lineup assembly C. This assembly comprises an outer tubular body 70 which is connected in the pipe string 14. The body is formed with longitudinal recesses 71 which have ribs or guide elements 72 removably secured therein. As shown in FIGURE 10, each guide element 72 is in the form of an elongate bar which is secured to the body 70 through suitable screws 73. The exterior surface 74 of each guide bar is arranged to substantially contact the inner surface of the bore a of the casing 10. A plurality of the guide bars or elements 72 are provided and form a lineup or guide arrangement which will effectively guide the replacement section 110 of the easing into final position.

In the use of the apparatus shown in FIGURES 4 and 5, the apparatus is lowered into the casing and the device B locates a collar so as to position the cutters 15 of the cutting tool between couplings in the casing string. The apparatus is then raised slightly in the manner described with respect to FIGURE 2 and the cutting operation is carried out to sever the casing at the point 25 and thereafter the defective portion of the casing is removed. At this point, it is possible to raise the apparatus, as illustrated in FIGURE 5, and to engage the dogs 17 of the device B with the recess 11a of that casing collar 11 which is just below the upper end 10b of the casing still remaining in the hole. When the device A is supported at this point, the line-up assembly C is disposed to span the point which will be formed between the replacement section 110 of casing and the portion of the casing still remaining within the bore. This position of the parts is illustrated in FIGURE 5. Thereafter, the replacement section may be run into the well bore and the line-up assembly C will function to accurately guide the replacement section into place over the upper end of the casing which remains in the well bore. Of course, it is evident that the apparatus can be moved to the position of FIG- URE 5 either immediately following the cutting operation or at any time prior to the final guiding of the replacement section into its final position.

In the forms of apparatus shown and described in FIG- URES 1 to 5, the collar finder device B has been employed, first to locate the collar and properly position the cutting tool and to thereafter function as a support for supporting the apparatus within the well bore while the defective portion of the casing is removed and the replacement section is run. Although this has been found satisfactory, it will be recognized that the collar finder device can be located only at a collar in the casing string and there may be times when it is desirable to support the apparatus at points other than at a particular collar. In order to accomplish this, the assembly of FIGURE 6 may be employed.

By reference to FIGURE 6 it will be seen that the apparatus includes the lowering pipe 14, the cutter tool A, the line-up assembly C, the collar finder device B and a supporting tool D. As will be explained, the supporting tool D includes gripping slips which are adapted to be expanded by manipulation of the pipe string 14 so that said slips may be actuated to engage the Wall of the casing 10 to support the entire apparatus therein.

In using the apparatus of FIGURE 6, said apparatus is run into the hole and the collar finder device B is utilized to locate a collar and properly position the cutters 15 of the cutting tool A. Thereafter, the apparatus is slightly raised to move the dogs 17 of the device B out of the recess 11a of the casing collar 11 and the cutter tool A actuated so that its cutters sever the casing at the desired point. Thereafter, instead of again actuating the collar finder device B to expand its dogs 17, the supporting tool D is actuated to expand its slips 80 and said slips engage the wall of the casing which is still within the well bore. Thus, the tool D functions to support the apparatus and the inner pipe While the upper defective section of the casing is removed and the replacement section is run into the bore. Since the line-up assembly C is located below the cutter A, it will be evident that the line-up tool should be positioned to span the joint formed between the replacement section of casing and that portion of the casing still remaining in the hole. This can be done immediately following the cutting operation by raising the apparatus and properly setting the slips 80 of the supporting tool. However, it would be possible to support the entire apparatus downwardly within the portion of the casing still remaining in the bore and just prior to the time that the replacement section moves into final position, the inner pipe may be raised and the supporting tool reset so as to locate the line-up assembly C in position spanning the joint which is to be made. If desired, a second line-up assembly indicated by the dotted lines C in FIGURE 6 may be connected to the string 14 above the cutter tool A. In such case the lineup assembly C below the cutter may be eliminated and, obviously, the support tool could be actuated immediately following cutting so that the apparatus is supported within the casing in substantially the same position the apparatus had during the cutting operation. The line-up assembly C above the cutting tool would function to guide the replacement section 110 of casing into final position for connection with the upper end b of the casing remaining in the well bore. It is apparent that various combinations and positions of the elements making up the apparatus may be used in accordance with the particular practice which the operator may desire.

In FIGURE 6 the apparatus is shown as having the cutter tool A above the line-up assembly C with the collar finder B located below said line-up assembly. However, as above noted, the element may be arranged in any desired order and in FIGURE 7 the cutter tool A is shown as having the collar finder B immediately therebelow. Below the collar finder device, the line-up assembly C is connected and below such assembly the supporting tool D is mounted. In the use of the apparatus of FIGURE 7, the operation would be substantially the same as that of FIGURE 6 except that when the line-up assembly C is required to guide the replacement section, the entire apparatus would have to be lifted upwardly and the support tool set in the upper portion of the easing still remaining in the hole, whereby the line-up assembly will properly span the joint to be made between the replacement section and the casing Within the bore.

Although various types of supporting tools may be employed, one type Which has been found satisfactory is illustrated in FIGURE 12. This particular supporting tool is somewhat similar in construction to the collar finder device which has been heretofore described. As shown in FIGURE 12, the tool D includes a central mandrel 90 which extends entirely through the tool and which has an elongate sleeve or collar 91 threaded onto its lower end. The collar is formed with radially extending pins 92 which are adapted to engage a J-slot 93 provided in a sleeve 94 secured to an outer casing 95, the latter encircling the mandrel 90.

Disposed between the outer housing 95 and the mandrel 90 is an elongate sleeve 96 having an expander 97 at its upper end. The expander is adapted to co-act with radially movable slip elements 98 and said outer housing is also provided with friction drag shoes 99. It is evident that when the expander 97 is in a raised position with respect to the slips 98; said slips are in a retracted position. However, upon a downward relative movement of the expander 97 with respect to the slips, said slips are urged radially outwardly into gripping position.

In the operation of the supponting tool D, the parts thereof are in the position shown in FIGURE 12 with the pin 92 engaged within the J-slot 93- whereby the mandrel 90 is, in effect, connected with the outer casing or housing 95. At this time, the slips 98 are in a retracted position. When it is desired to set said slips, the mandrel 90 is rotated to align the pins '92; with the longitudinal portions of the J-slots 93 whereby downward movement of the mandrel 90 with respect to the outer housing 95 may occur. Since the expander sleeve 96 is supported by the sleeve 91 which is secured to the mandrel 90*, the downward motion of the mandrel will cause the expander 97 to expand the slips 98 into their gripping position; the outer housing 95 is, of course, held stationary during this motion by reason of the friction shoes 99.

When it is desired to retract the slips 98, it is only ncessary to move the mandrel 9t} upwardly with respect to the outer housing 95 and to re-engage the pins 97 in the upper or lateral portions of the J-slot so as to lock the outer casing or housing to the mandrel in the position shown in FIGURE 12. Just as in the case of the collar finder device, it is obvious that the slips may be expanded and retracted selectively and as many times as desired merely by connecting and disconnecting the J-slot attachment between the mandrel and the outer housing.

It is pointed out that if desired the supporting tool D may be provided with the automatic bottom type of connection which is illustrated in FIGURE 11 with respect to the collar finder device. In FIGURE 12a this type of connection is shown as attached to the lower end of the mandrel 90. In such case the collar 51 would be attached to the mandrel and the supporting bowl 55 of the automatic bottom connection would be attached to the lower end of the outer housing 95. The operation would, of course, be as heretofore described with respect to this automatic bottom type of connection.

It is pointed out that where the collar finder device B and the support too] D are employed in the same apparatus in the manner shown in FIGURES 6 and 7, it is desirable that the collar finder device have one type of connection with its mandrel while the supporting tool have the other type of connection. In other words, in order to permit selectivity of which device will be operated, the collar finder device is illustrated with the automatic bottom connection while the support tool is illustrated with the J-slot type of connection. It would be possible to provide the automatic bottom on the supporting tool and the J-type connection on the collar finder device B. So long as the connections are different, the operator may selectively operate one or the other. For example, with the collar finder device B having the automatic bottom connection, a rotation to the right of the pipe would disconnect said connection and allow expansion of the locking dogs .17. Such rotation would not affect the J-slot connection. Merely by lifting upwardly on the pipe, the connection may be remade between the housing 56 and the mandrel 50 of the collar finder device B to again retract these dogs. Thus, the device B may be selectively actuated Without affecting the supporting tool D. Similarly, if the slips 98 are to be set, the pipe is partially rotated and then moved downwardly. This partial rotation is not sufficient to disengage the automatic bottom connection but is suificient to disconnect the J and upon downward movement the slips 98 are set. It is thus possible to mount both the collar finder device and the supporting tool in the same string and to selectively actuate the same to carry out the methods as heretofore described.

From the foregoing it will be seen that a relatively simple type of apparatus is provided whereby an improved method of repairing casing strings is provided. In its simplest form the apparatus includes a suitable tool, either hydraulically or mechanically actuated, with a collar finder device having the dual function of properly locating the tool and subsequently supporting the apparatus. Also, the cutter tool may be utilized as a guide or line-up element so that an extremely simple assembly is had. However, where desired, a separate line-up assembly such as that shown at C may be provided and where it is desired to support the apparatus at a point other than a casing collar, the supporting tool may be added. Wk

In accordance with the methods disclosed, the apparatus may be located to sever or cut the casing and then may be supported at substantially that position in order to function as a guide for the replacement section; or if desired the tool may be moved downwardly and supported in that portion of the casing still remaining and at some time prior to the final positioning of the replacement portion of the casing, the line-up element is properly positioned to span the joint. The apparatus is extremely versatile and can be manipulated in any desired manner in accordance with the particular conditions encountered.

The foregoing disclosure and description of the invention is illustrative and explanatory thereof and various changes in the size, shape and materials, as well as in the details of the illustrated construction, may be made within the scope of the appended claims without departing from the spirit of the invention.

What I claim is:

1. An apparatus for removing a defective well pipe section and for guiding a replacement section of pipe into place including, an inner lowering pipe, an inside pipe cutter tool mounted on the lowering pipe, line-up and guide means carried by the lowering pipe and having a guide surface fitting within the bore of the pipe to be repaired, a collar finder device mounted on said lowering pipe and spaced from the cutter tool including means to properly locate said cutter tool with respect to a collar, said cutter tool including means for actuating the cutter tool to sever the well pipe at a point below the defect therein, and means engageable with the well pipe below the point of severance for supporting the cutter tool and line-up and guide means as well as the lowering pipe, whereby the upper defective section of the well pipe may be severed by said cutter tool and removed by stripping the same over the lowering pipe and also whereby said lowering pipe and the line-up and guide means subsequently guide a replacement section of well pipe into proper position within the well.

2. An apparatus as set forth in claim 1, wherein the cutter tool has an outside body and also wherein the outer diameter of the outer body of the cutter tool is such that said body is adapted to fit with a relatively small clearance within the bore of the well pipe to be repaired, whereby said body functions as the line-up and guide means.

3. An apparatus as set forth in claim 1, wherein the means for supporting the cutter tool, line-up and guide means and lowering pipe is the collar finder device which is formed with expansible elements engageable with the recess of one of the coupling collars of the well pipe.

4. An apparatus as set forth in claim 1, wherein the line-up and guide means comprises a body connected in the lowering pipe string, and radially projecting longitudinal guide elements removably secured to the exterior of said body, the outer surfaces of said elements fitting within the bore of the well pipe to be repaired.

5. An apparatus as set forth in claim 1, wherein the inside pipe cutter tool is hydraulically actuated by pressure applied through the lowering pipe.

6. An apparatus as set forth in claim 1, wherein the inside pipe cutter tool is mechanically actuated by manipulation of the lowering pipe.

7. An apparatus for removing a defective well casing section and for guiding a replacement section of casing into place including a lowering pipe upon which the apparatus is adapted to be lowered within the well casing, an inside pipe cutter tool having expansible cutting members, said cutter tool being mounted on said lowering pipe at the lower end thereof, means forming part of said inside pipe cutter tool and coacting with the expansible cutter elements for controlling expansion and retraction thereof, the outer diameter of the outer body of the cutter tool being such that said body fits with a relatively small clearance within the bore of the well casing, a line-up assembly mounted on said lowering pipe and spaced from said cutter tool, and a collar finder device mounted on the lowering pipe below the cutter tool, said collar finder including radially expansible elements for engagement with the recess in one of the coupling collars of the well casing to be repaired, expander means coacting with the expansible elements and actuated by manipulation of the lowering pipe to control expansion and retraction of said elements, and releasable means coacting with said expander means to release said expander means by manipulation of said lowering pipe, said expansible elements of the collar finder being expanded by the expander means to engage with the recess of one of the well casing coupling collars to locate said cutter tool and the lower portion of the lineup assembly within that portion of the well casing below the point of severance, said expansible elements of the collar finding device being retracted by said manipulation of the lowering pipe to permit actuation of the cutter tool to severe the casing, and thereafter expanded to support the apparatus, whereby the defective section may be removed by stripping the same over the lowering pipe and also whereby a replacement section of casing is guided into place by said lowering pipe and said line-up assembly.

8. An apparatus as set forth in claim 7, wherein the line-up assembly is mounted below the cutter tool and above the collar finder device.

9. An apparatus as set forth in claim 7, wherein the inside cutter tool is hydraulically actuated by pressure fluid applied through the lowering pipe.

10. An apparatus as set forth in claim 9, wherein the inside cutter tool is mechanically actuated by manipulation of said lowering pipe.

11. A method of replacing a defective casing section of a well casing located in a well bore which casing includes a plurality of well pipe sections coupled together by connecting collars, comprising the steps of lowering an apparatus including an inside cutter tool and a line-up element into the well casing on an inner pipe string, utilizing one of the connecting collars as an index position to locate the cutter tool in proper position within the casing, operating the cutter tool to sever the casing at a point below the defective casing section, thereafter supporting the apparatus and the inner pipe within the casing below the point of separation with the line-up element spanning the cut portion of the casing prior to removing the upper defective section, while the apparatus and inner pipe remain supported within the well thus locating the line-up element in a position to guide the lower end of a replacement section of casing, and thereafter lowering a replacement section of casing into the well bore into final position by threading the same over the inner pipe and relative to the upper end of the casing still remaining in the well bore.

12. A method of replacing a defective casing section of a well casing located in a well bore which casing includes a plurality of well pipe sections coupled together by connecting collars, comprising the steps of, lowering an apparatus including an inside cutter tool and a line-up element, positioning the cutter tool below the defect in the casing, operating the cutter tool to sever the casing at a point below the defective casing, thereafter supporting the apparatus and inner pipe within the well bore below the point of separation with the line-up element spanning the cut portion of the casing prior to removing the upper defective section by utilizing the wall of the pipe below the defect as a supporting surface, removing the defective casing section from the well bore by stripping it over the inner pipe, thus locating the line-up element in a position to guide the lower end of a replacement section of casing, and thereafter lowering a replacement section of casing into the well bore into final position by threading it over the inner pipe and relative to the upper end of the casing still remaining in the well bore.

13. The method as set forth in claim 11, with the additional steps of connecting the replacement section of casing to the casing in the well bore by a connecting patch, and finally removing the apparatus and inner pipe from the repaired casing. 1

14. The method as set forth in claim 12, wherein the locating of the line-up element in proper position to perform its guiding is accomplished by moving the entire References Cited in the file of this patent UNITED STATES PATENTS Yancey Sept. 13, Robichaux et a1. Nov. 4, ONeill Jan. 6, Dill Feb. 24, Mitchell May 22, Woolley Aug. 19, 

1. AN APPARATUS FOR REMOVING A DEFECTIVE WELL PIPE SECTION AND FOR GUIDING A REPLACEMENT SECTION OF PIPE INTO PLACE INCLUDING, AN INNER LOWERING PIPE, AN INSIDE PIPE CUTTER TOOL MOUNTED ON THE LOWERING PIPE, LINE-UP AND GUIDE MEANS CARRIED BY THE LOWERING PIPE AND HAVING A GUIDE SURFACE FITTING WITHIN THE BORE OF THE PIPE TO BE REPAIRED, A COLLAR FINDER DEVICE MOUNTED ON SAID LOWERING PIPE AND SPACED FROM THE CUTTER TOOL INCLUDING MEANS TO PROPERLY LOCATE SAID CUTTER TOOL WITH RESPECT TO A COLLAR, SAID CUTTER TOOL INCLUDING MEANS FOR ACTUATING THE CUTTER TOOL TO SEVER THE WELL PIPE AT A POINT BELOW THE DEFECT THEREIN, AND MEANS ENGAGEABLE WITH THE WELL PIPE BELOW THE POINT OF SEVERANCE FOR SUPPORTING THE CUTTER TOOL AND LINE-UP AND GUIDE MEANS AS WELL AS THE LOWERING PIPE, WHEREBY THE UPPER DEFECTIVE SECTION OF THE WELL PIPE MAY BE SEVERED BY SAID CUTTER TOOL AND REMOVED BY STRIPPING THE SAME OVER THE LOWERING PIPE AND ALSO WHEREBY SAID LOWERING PIPE AND THE LINE-UP AND GUIDE MEANS SUBSEQUENTLY GUIDE A REPLACEMENT SECTION OF WELL PIPE INTO PROPER POSITION WITHIN THE WELL.
 11. A METHOD OF REPLACING A DEFECTIVE CASING SECTION OF A WELL CASING LOCATED IN A WELL BORE WHICH CASING INCLUDES A PLURALITY OF WELL PIPE SECTION COUPLED TOGETHER BY CONNECTING COLLARS, COMPRISING THE STEPS OF LOWERING AN APPARATUS INCLUDING AN INSIDE CUTTER TOOL AND LINE-UP ELEMENT INTO THE WELL CASING ON AN INNER PIPE STRING, UTILIZING ONE OF THE CONNECTING COLLARS AS AN INDEX POSITION TO LOCATE THE CUTTER TOOL IN PROPER POSITION WITHIN THE CASING, OPERATING THE CUTTER TOOL TO SEVER THE CASING AT A POINT BELOW THE DEFECTIVE CASING SECTION, THEREAFTER SUPPORTING THE APPARATUS AND THE INNER PIPE WITHIN THE CASING BELOW THE POINT OF SEPERATION WITH THE LINE-UP ELEMENT SPANNING THE CUT PORTION OF THE CASING PRIOR TO REMOVING THE UPPER DEFECTIVE SECTION, WHILE THE APPARATUS AND INNER PIPE REMAIN SUPPORTED WITHIN THE WELL THUS LOCATING THE LINE-UP ELEMENT IN A POSITION TO GUIDE THE LOWER END OF A REPLACEMENT SECTION OF CASING, AND THEREAFTER LOWERING A REPLACEMENT SECTION OF CASING INTO THE WELL BORE INTO FINAL POSITION BY THREADING THE SAME OVER THE INNER PIPE AND RELATIVE TO THE UPPER END OF THE CASING STILL REMAINING IN THE WELL BORE. 